Ask about a page instead of looking at it

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Goes well beyond the readOnlyHint=true annotation by disclosing the key behavioral trait: the page never enters the agent's context, so the call costs hundreds of tokens instead of tens of thousands. It also discloses the degenerate mode ('without a model, it returns the passages relevant to your question instead'), which changes what the caller should expect to receive.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three tight sentences, front-loaded with what the tool does and the cost rationale, with the fallback behavior last. Each sentence carries distinct information — purpose, cost benefit, degraded mode — with no restatement of the name or schema.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description carries the burden of describing returns and does so ('a short answer' or 'the passages relevant to your question'). What is missing is any mention of error behavior (unreachable tab, invalid tabId), which an agent may need for a tool that depends on live browser state.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so both parameters (tabId default-to-active-tab, question) are already documented in the schema, including the example question format. The description adds no further parameter detail, so the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Ask a question about what is on a browser tab') and immediately explains the mechanism ('Deputy reads the page itself and returns a short answer'). The contrast with 'screenshotting or dumping the DOM' functionally separates it from browser_screenshot, browser_read, and browser_eval without the agent needing to open their schemas.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives a clear selection rule: 'Use this instead of screenshotting or dumping the DOM,' which routes the agent away from heavier siblings when only a lookup is needed. It does not state a when-not case (e.g., when you actually need raw page content you should use browser_read/browser_extract), so it stops short of full routing guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.